Mirror operating arrangement of single lens reflex camera

ABSTRACT

A mirror operating arrangement for a single lens reflex camera in which during mirror operation the mirror rotation shaft moves from a viewing position to a shutter operating position is disclosed. In an individual mirror-up operation, the mirror is swung up without causing the mirror rotation shaft to be moved to the shutter operating position. Upon photographing operation, after the individual mirror-up operation, the mirror rotation shaft is moved to the shutter operating position. The shock of the mirror operating arrangement is decreased by the mirror being previously swung up in the individual mirror-up operation.

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention relates to a mirror operating arrangement forinterchangeable lens type single lens reflex cameras.

With respect to the mirror operating arrangement of interchangeable lenstype single lens reflex cameras, a considerable number of so-calledretrogression type mirror operating arrangements have been devised andput into practice in order to solve the problems of image darkening andnarrowing upon utilizing telephoto lenses and the mechanical backrestrictions of interchangeable lenses. For cases in which camerashaking must be avoided to as great an extent as possible, such asmicroscopic and copying photography, individual mirror-up arrangementshave been put into practice to avoid mirror shocks.

In accordance with the present invention, upon individual manualmirror-up operation only the front portion of the mirror is moved up,and the remaining move-up action is utilized for shock absorbing of themirror driving member which has become stronger to the extent of theunnecessariness part of mirror driving power, at the time of shutterrelease action. The front part of the mirror is fully swung up as viewedfrom the mount upon lens removal. In the area of the lens attachingmount, the space is scarcely narrower when the mirror is swung up inaccordance with the present invention than when the whole mirror isfully swung up, so that the space for super wide angle lenses, fish eyelenses, and similar components which can only be attached with themirror swung-up, is almost equal to that of fully swung-up mirror cases.Such advantages can not be obtained if the mirror rotation shaft acts asa fixed fulcrum. Further, the shock absorbing arrangement of the presentinvention considerably decreases the operation noise, and the shockabsorbing action is automatically made upon photographing operationduring which time camera shaking should be avoided. The shock absorbingmember is the conventional mirror itself, so that the foregoingadvantages are economically attained without any new members solelyincluded for shock dampening purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of the mirror operating arrangementaccording to the present invention with the mirror in an initial viewingposition, with parts omitted for purposes of clarity;

FIG. 2 is an elevational view similar to FIG. 1 depicting the mirroroperating arrangement in a mirror-up position;

FIG. 3 is an elevational view similar to FIG. 1 depicting the mirroroperating arrangement in a shutter operating position; and

FIG. 4 is an elevational view of the mirror operating arrangement asviewed from the left side of FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS

In FIGS. 1, 2 and 3, a charge lever 1 is rotatably pivoted to a shaft Afixed to a mirror box main body 2 and is urged clockwise about the shaftA by a return spring 4 arranged between the end cutout 1a and the cameramain body 3. An operating lever 5 is also rotatably pivoted to the shaftA, and it overlies the charge lever 1 as shown in FIGS. 1, 2 and 3.Between a projection 1b of the reverse side of the charge lever 1 and aprojection 5a of the reverse side of the operating lever 5, there isprovided a power spring 6 so that the charge lever 1 is urged clockwisewhile the operating lever 5 is urged counterclockwise. In FIG. 1 the endportion 1c of the charge lever 1 abuts against the projection 5a so thatthe power spring 6 does not contract further than as shown in FIG. 1.

An engaging lever 7 is rotatably pivoted to a shaft C fixed to themirror box main body 2. In FIG. 1, the end portion 7a of the engaginglever 7 abuts against an engaging plate 5b fixed to the operating lever5. Between a projection 5c fixed to the surface of the operating lever 5and a projection 8a fixed to a diaphragm operating rod 8, which isrotatable about a shaft B fixed to the mirror box main body 2, there isarranged a stop-down spring 9 so that the diaphragm operating rod 8 isurged in a clockwise direction. A following element 5d projecting fromthe reverse side of the operating lever 5 comes into abutment against acam surface 8b at the end portion of the diaphragm operating rod 8 anddetermines the position of the diaphragm operating rod 8, that is, therod 8 does not further rotate in a clockwise direction.

The automatic diaphragm pin 10 of an interchangeable lens is normallyurged upward in the drawing by a spring (not shown). A so-called normalstop-down system is so arranged that an upward movement of the automaticdiaphragm pin 10 causes diaphragm blades of an interchangeable lens (notshown) to be closed. The pin 10 abuts against the end portion 8c of thediaphragm operating rod 8 as shown in FIG. 1. However, the downwardforce of the end portion 8c due to the stop-down spring 9 is greaterthan the upward urge of the automatic diaphragm pin 10, so that theposition of the automatic diaphragm pin 10 is determined by the positionof the end portion 8c of the diaphragm operating rod 8.

Between a pin 5e fixed to the surface of the operating lever 5 and a pin11a fixed to the surface of one end portion of a shutter arrangementdisengaging lever 11 which is rotatable about a shaft F fixed to themirror box main body 2, there is arranged a connecting rod 12, the pins5e and 11a rotatably engaging holes 12b and 12a, respectively. Thus, theoperating lever 5 and the disengaging lever 11 make nearly the sameangular movement.

A mirror-up lever 13, which is rotatable about a shaft D fixed to themirror box main body 2, is provided with a cam surface 13a which abutsagainst a pin 5f fixed to the surface of the operating lever 5 when thelever 5 rotates in a counterclockwise direction. Thus, acounterclockwise rotation of the operating lever 5 causes a clockwiserotation of the mirror-up lever 13.

A mirror-swing shaft supporting lever 14 is rotatably pivoted to theshaft D fixed to the mirror box main body 2 and a shaft D' which is alsofixed, as shown in FIG. 4, to the mirror box main body 2 in coaxialrelation with the shaft D. Between a projection 14a of the lever 14 anda projection 15 fixed to the mirror box main body 2, there is arranged atorsion spring 16 wound about the shaft D so that the mirror-swing shaftsupporting lever 14 is normally urged in counterclockwise direction inFIGS. 1 - 3. A mirror-swing shaft E fixed to the mirror-swing shaftsupporting lever 14 abuts against the lower edge of a cocoon-shaped hole19a of a stopper plate 19 fixed to the mirror box main body 2 withscrews 17 and 18, as shown in FIGS. 1 and 2, so that the lever 14 doesnot make further counterclockwise rotation.

A mirror 20 is rotatably supported in the following manner. As shown inFIG. 4, the shaft E and a shaft E', which is also fixed to themirror-swing shaft supporting lever 14 in coaxial relation with theshaft E, engage holes 21b and 21b', respectively, of angles 21 and 21'fixed to the mirror 20. A torsion spring 22 is arranged between the endportion 14b of the lever 14 and a projection 21a fixed to the angle 21and is wound about the shaft E. This torsion spring 22 urges the mirror20 in a clockwise direction in FIG. 1. The mirror 20 abuts against amirror stopper 23 fixed to the reverse side of the mirror box main body2 and stops as shown in FIG. 1.

When the wind-up lever (not shown) of the camera is actuated in awind-up operation, a charge member 24 moves to the right until itreaches a position 24', and then it returns to the left until it reachesthe position 24, as shown in FIG. 1. During this operation, the chargemember 24 abuts against the edge 1d of a charge lever 1 and causes thecharge lever 1 to make counterclockwise rotation until it reaches aposition 1', when an engaging member 25, which moves perpendicularly tothe plane of the paper of FIG. 1, enters the rotation range and fixesthe charge lever 1 to the position 1'. The operating lever 5, which isurged in counterclockwise direction by the power spring 6, remainsengaged as shown in FIG. 1, since the engaging plate 5b engages the endportion 7a of the engaging lever 7. For this reason, the power spring 6is extended from the length 5a - 1b to the length 5a - 1b' and storespower. The return spring 4 is also extended in the same manner.

Then, when the release button (not shown) is depressed for photographingoperation, a disengaging member 26 moves downward (from the state ofFIG. 1 to the state of FIG. 3), so that a force is applied to the edge7b of the engaging lever 7, which edge 7b abuts against the member 26,causing the engaging lever 7 to be rotated in a counterclockwisedirection. Then, as shown in FIG. 3, the engaging plate 5b is disengagedfrom the end portion 7a, so that the power spring 6 causes the operatinglever 5 to be rotated in a counterclockwise direction.

The counterclockwise rotation of the operating lever 5 causes thefollowing element 5d to push the diaphragm operating rod 8 at the camsurface 8b so that the diaphragm operating rod 8 makes acounterclockwise rotation against the force of the stop-down spring 9.Accordingly, the end portion 8c of the rod 8 withdraws upward, so thatthe automatic diaphragm pin 10 moves upward due to the force of a springarranged in the mechanism of the interchangeable lens (not shown) untilit reaches a position 10', when diaphragm-blade stop-down operation iscompleted.

The counterclockwise rotation of the operating lever 5 also causes themirror-up lever 13 to make a clockwise rotation so that the end portion13b of the lever 13 abuts against the projection 21a of the angle 21 andcauses the mirror 20 to be rotated in a counterclockwise directionagainst the force of the torsion spring 22. Since the mirror 20 has agreat moment of inertia in this arrangement, simultaneously with pushingup of the projection 21a by the end portion 13b of the mirror-up lever,a force is applied through the mirror rotating shaft E tending to pushup the supporting lever 14 against the force of the torsion spring 16.However, a pin 14c fixed to the supporting lever 14 abuts against theend portion 11b of the shutter arrangement disengaging lever 11 so thatthe supporting lever 14 does not move.

When the mirror-up lever 13 has caused the mirror 20 to makecounterclockwise rotation by about 45° from the position of FIG. 1, theshutter arrangement disengaging lever 11 rotates in a counterclockwisedirection up to the dot-dot-and-dash line position of FIG. 1, so thatthe mirror rotation shaft supporting lever 14 becomes able to makeclockwise rotation. At the same time, the edge 13c of the mirror-uplever 13 abuts against the pin 14c. After this, the mirror-up lever 13and the mirror rotation shaft supporting lever 14 make an angularmovement as one body until they reach the state of FIG. 3, then theshaft E abuts against the upper edge of the cocoon-shaped hole 19a, andthe mirror 20 reaches its fully swung position. The counterclockwiserotation of the operating lever 5 causes the shutter arrangementdisengaging lever 11 to make counterclockwise rotation, so that the edge11c of the lever 11 abuts against a shutter arrangement engaging member27 in the state of FIG. 1 and pushes it to the left up to the positionof FIG. 3. Accordingly, the shutter arrangement begins to operate.

In the return operation, a signal of completion of the operation of theshutter arrangement is transmitted to the engaging member 25 so that theengaging action of the engaging member 25 is eliminated. Accordingly,due to the force of the return spring 4, the charge lever 1 makes aclockwise rotation, and also the operating lever 5 makes a clockwiserotation. Then, in entirely reverse order with respect to the order ofthe above mentioned operation, the whole arrangement returns to itsinitial state with the end portion 7a of the engaging lever abuttingagainst the engaging plate 5b, so that preparation for the next wind-upoperation is completed.

When the diaphragm is to be individually manually stopped down, themanual stop-down button (not shown) of the camera is depressed. Then, asshown in FIG. 1, a stop-down member 28 moves upward into abutmentagainst the projection 8a to the position shown at 28' causing thediaphragm operating rod 8 to make counterclockwise rotation against theforce of the stop-down spring 9 so that the automatic diaphragm pin 10moves to the position 10' and the stop-down operation is completed. Whenthe manual stop-down button is released, the stop-down member 28 returnsfrom the position 28' to the position 28, the diaphragm operating rod 8makes a returning movement owing to the action of the stop-down spring 9and the automatic diaphragm pin 10 returns from the position 10' to theposition 10 against the spring force acting in the direction of from 10to 10' so that the diaphragm becomes fully open.

When the mirror is to be individually swung up, the individual mirror-upmember (not shown) of the camera is actuated. Then, the mirror-up member29 of FIG. 1 moves upward into abutment against a pin 13d fixed to themirror-up lever 13 and causes the lever 13 to make clockwise rotation.As a result, as shown in FIG. 2, an end portion 13b pushes upward theprojection 21a of the angle 21 against the force of the torsion spring22, so that the mirror 20 makes counterclockwise rotation into aposition in which the mirror 21 stops with the end portion lifted, asshown in FIG. 2. At this time, a force tending to cause clockwiserotation is applied through the shaft E to the mirror rotation shaftsupporting lever 14. However, since the end portion 11b of the shutterarrangement disengaging lever abuts against the pin 14c, the mirrorrotation shaft supporting lever 14 makes scarcely any movement.

When photographing operation is made with individual mirror-up, therelease button is depressed, the engaging lever end portion 7a isdisengaged from the engaging plate 5b, and the operating lever 5 makescounterclockwise rotation. Then, the pin 5f moving to the left is offfrom the cam surface 13a of the mirror-up lever 13 in the position asshown in solid line in FIG. 2 in the early part of the rotationmovement, then, at nearly the end of the rotation movement, the pin 5fabuts against the cam surface 13a and causes the mirror-up lever 13 tomake clockwise rotation so that the end portion 13b pushes up theprojection 21a of the angle 21. As a result, the mirror rotation shaftsupporting lever 14 moves from the position of FIG. 2 to the position ofFIG. 3, so that the mirror 20 is fully swung up as shown in FIG. 3. Whenthe operating lever 5 has made counterclockwise rotation up to suchposition that the end portion 13b of the mirror-up lever 13 comes intoabutment against the projection 21a of the angle 21, the end portion 11bof the shutter arrangement disengaging lever has escaped to the rightfrom the position in which it abuts against the pin 14c, so that themirror rotation shaft supporting lever 14 is not prevented from makingclockwise rotation.

The pin 14c acts as mentioned above. Now, if this pin 14c does notexist, the object can be attained by making the force of the torsionspring 16 applying counterclockwise urge to the lever 14 considerablystronger, but this is accompanied by a disadvantage that the force ofthe power spring 6 must be made stronger.

In conventional individual mirror-up photographing operation, the mirroris fully swung up so that a shock is produced through the power springaction which is made stronger to the extent of the unnecessariness partof the mirror swing-up action. Now, according to the present invention,the mirror is first moved halfway up, and then, upon shutter releaseaction, in the last stage of the power spring action the mirror isfurther moved up, so that there is obtained an advantage that the shockis absorbed to the extent of the further upward movement of the mirrorso as to produce a buffer effect.

What is claimed is:
 1. In combination, a mirror and a mirror mountingassembly for movably mounting said mirror in a single lens reflex camerawith reduced shock loads upon movement of said mirror to a shutteroperating position, said mirror mounting assembly comprising mountinglever means providing a generally horizontal, upwardly translatablemirror rotation axis for supporting said mirror adjacent an end of saidmirror in a viewing position, said mirror being rotatable about saidmirror rotation axis, in a first position of the axis, from said mirrorviewing position to translate the free end of the mirror in an upwarddirection and thereby position the mirror at an angularly displacedmirror-up position prior to shutter operation, said mounting lever meansbeing adapted to be supported in a camera for rotational movement totranslate said mirror rotation axis from said first axis position andsaid mirror from its mirror-up position further in said upward directionand to said shutter operating position.
 2. The combination as set forthin claim 1 wherein said mounting lever means are adapted to be supportedin a camera at a lever rotation axis located adjacent an end of saidmounting lever means, and said mirror rotation axis comprises swingshaft means secured to said mirror and carried by said mounting levermeans adjacent an opposite end of said mounting lever means remote fromsaid lever rotation axis.
 3. The combination as set forth in claim 2wherein said swing shaft means are upwardly translatable withinelongated guide means adapted to be fixed to a camera.
 4. Thecombination as set forth in claim 1 wherein said mounting lever meansinclude pin means arranged to cooperate with shutter operating meanscarried by a camera to prevent shutter operation prior to thetranslation of said mirror to said mirror-up position.
 5. A method ofreducing the shock upon movement of a mirror in a single lens reflexcamera from a viewing position to a remote shutter operating positioncomprising supporting said mirror in a viewing position for rotationalmovement about a mirror rotation axis adjacent one end of the mirror,rotating said mirror about said mirror rotation axis, in a firstposition of the axis, to translate the free end of the mirror in anupward direction and thereby position the mirror at an angularlydisplaced mirror-up position prior to shutter operation, and then, uponshutter operation, translating said mirror rotation axis from said firstaxis position and said mirror from its mirror-up position further insaid upward direction to said remote shutter operation position.
 6. Amethod as set forth in claim 5 wherein the step of rotating said mirrorabout said mirror rotation axis includes moving said free end of themirror to substantially said remote shutter operating position.
 7. Amethod as set forth in claim 5 wherein the step of translating saidmirror rotation axis and said mirror includes both rotational andnonrotational movement.
 8. A method as set forth in claim 5 wherein thestep of rotating said mirror about said mirror rotation axis includesmovement in a first angular direction, and the step of translating saidmirror rotation axis and said mirror includes movement in a secondangular direction opposite to said first angular direction.